This project is aimed at understanding the psychophysical and neurophysiological basis of form perception in two- and three-dimensional space. The general research paradigm used is target detection in visually noisy space. The general theoretical approach is based upon an autocorrelational transform that assumes that the processing of visual images is carried out by a distributed nerve net, rather than by feature-filtering individual neurons. A good correspondence has been shown in the past between the model and the psychophysical data. BIBLIOGRAPHIC REFERENCES: Uttal, W. R., Fitzgerald, J., and Eskin, T. E. Parameters of tachistoscopic stereopsis. Vision Research, 1975, 15, 705-712. Uttal, W. R., Fitzgerald, J., and Eskin, T. E. Rotation and translation effects on stereoscopic acuity. Vision Research, 1975, 15.